1. Field of the Invention
The invention relates to fiber optic connector inspection and more particularly to a dual-purpose adapter for inspecting circular ruggedized fiber optic connectors using an inspector probe. The dual-purpose adapter according to this invention may be connected to an inspector probe in two opposite directions, one for inspecting Physical Contact (“PC”) connector endfaces and the other for inspecting Angled Physical Contact (“APC”) connector endfaces embedded in the circular ruggedized fiber optic connector.
2. Description of the Related Art
Robust fiber optic interconnects are needed in harsh environments. For example, military and aerospace systems must perform in hostile climates, inclement weather and adverse surroundings. Similarly, geophysical applications, emergency deployable communication systems, broadcasting, and security applications, etc. subject interconnects to demanding conditions. As a result, various kinds of so-called ruggedized fiber optic connectors capable to perform in harsh environments and demanding conditions have been developed and applied.
Two common types of ruggedized fiber optic connectors are the plug-type and the receptacle-type. A plug-type ruggedized connector 30 is shown in FIG. 1 and FIG. 2, and a receptacle-type ruggedized connector 50 is shown in FIG. 10. In either the plug-type ruggedized connector 30 or the receptacle-type ruggedized connector 50, a plurality of fiber optic termini 330 extend through the rear side of the ruggedized connector 30/50 and are fixedly held in a circular cylindrical holding block 32/52; each of the fiber optic termini 330 has a fiber optic endface 331 exposed in an open chamber 320/520 surrounded by an outer shell 310/510 and facing the front side of the respective ruggedized connector 30/50. In most cases, the fiber optic endface 331 is either a PC endface 3311 (as shown in FIG. 6) or an APC endface 3312 (as shown in FIG. 7). The PC endface is perpendicular to the axis of the fiber optic terminus 330, whereas the APC endface is tilted from the perpendicular plane (i.e. a plane that is perpendicular to the axis of the fiber optic terminus 330) by an angle α, which will be referred to as the “tilted angle” in the following. The tilted angle of APC endfaces is almost always 8°. The fiber optic endfaces 331 of the fiber optic termini 330 are arranged in a certain regular pattern, usually symmetrically or equiangularly (relative to the center of the holding block 32/52, depending upon the particular connector models and applications.
In the plug-type ruggedized connector 30, two diametrically placed guide pins 340 protrude forward from the holding block 32 into the open chamber 320. The guide pins 340 are intended for proper alignment and contact of the fiber optic termini 330 with the termini of another matching ruggedized connector (not shown). In contrast, in the receptacle-type ruggedized connector 50, no guide pins are equipped; instead, two diametrically placed locating holes 521 are formed in the holding block 52 for proper alignment and contact with termini of another matching ruggedized connector (not shown).
FIG. 1 and FIG. 2 illustrate a conventional adapter 7 for inspecting the plug-type ruggedized connector 30 with PC endfaces 3311 using an inspector probe 10. The conventional adapter 7 comprises a guide 70 and a fitting tip 73. As shown in FIG. 1, the guide 70 has two locating holes 729 corresponding to the two guide pins 340 of the plug-type ruggedized connector 30, and a plurality of light channels 720 corresponding (in number and relative positions) to the plurality of PC endfaces 3311 embedded in the plug-type ruggedized connector 30. When the guide 70 is coupled with the front end 314 of the plug-type ruggedized connector 30 by inserting the front portion 710 of the guide 70 into the open chamber 320 of the plug-type ruggedized connector 30 and mating the two locating holes 729 with the two guide pins 340, the front annular surface 713 of the guide 70 will be stopped at the front end 314 of the plug-type ruggedized connector 30 and the plurality of light channels 720 will correspond in relative position to the plurality of the PC endfaces 3311, respectively. Namely, each PC endface 3311 will be placed in the middle of one respective light channel 720 when viewed from the rear side of the guide 70. When the fitting tip 73 is fitted on the front end 101 of the inspector probe 10, the optical axis 100 of the inspector probe 10 will be collinear with the central axis 730 of the fitting tip 73. The fitting tip 73 has a front stem 732 which can be fittingly inserted into each of the light channels 720 of the guide 70 through the rear section 722 until the front end surface 731 of the fitting tip 73 comes in contact with an inner end surface 7221 of the rear section 722. After the guide 70 is coupled with the plug-type ruggedized connector 30, the fitting tip 73 is inserted into one of the light channels 720 of the guide 70, and the fitting tip 73 is connected with the front end 101 of the inspector probe 10, the endface 331 that is in view through the light channel 720 into which the fitting tip 73 is inserted may be inspected by the inspector probe 10. By repeating these steps, all the PC endfaces 3311 of the plug-type ruggedized connector 30 may be inspected one by one.
However, no conventional adapters have been made available for inspecting the plug-type ruggedized fiber optic connectors with APC endfaces 3312 using the inspector probe 10, nor are there any conventional adapters for inspecting receptacle-type ruggedized fiber optic connectors 50 with PC endfaces 3311 or APC endfaces 3312. Granted that specialized adapters may be designed for the APC endfaces and for the receptacle-type ruggedized connectors 50, it would be very cumbersome and costly to keep all the different adapters around for all the connector inspection tasks,
Therefore, a simple, compact, and multi-purpose adapter that enables an inspector probe 10 to inspect both types of ruggedized connectors, and for both PC and APC endfaces, will be very convenient and useful to carry out the inspection tasks, considering the critical importance of ruggedized connectors in the broad range of applications.